Definition of tough

tough - adj. resistant to cutting or chewing; physically toughened; not given to gentleness or sentimentality; feeling physical discomfort or pain (`tough' is occasionally used colloquially for `bad'); substantially made or constructed; making great mental demands; hard to comprehend or solve or believe; very difficult; severely testing stamina or resolution; unfortunate or hard to bear; violent and lawless; noun a cruel and brutal fellow; an aggressive and violent young criminal; someone who learned to fight in the streets rather than being formally trained in the sport of boxing.